Method and apparatus for treating cloth-end threads in a sewing machine



p 1969 TETSUO IIZUKA METHOD AND APPARATUS FOR TREATING CLOTH-END THREADSIN A SEWING MACHINE Filed Aug. 22, 1967 3 Sheets-Sheet 1 IN VENTOR.

P 9, 1969 TETSUO IIZUKA 3,465,702

METHOD AND APPARATUS FOR TREATING CLOTH-END THREADS m A snwme MACHINEFiled Aug. 22, 1967 3 Sheets-Sheet 2 P 9, 1969 'TETSUO IIZUKA 3,465,702

METHOD AND APPARATUS FOR TREATING CLOTH-END THREADS IN A SEWING MACHINEFiled Aug. 22, 1967 3 Sheets-Sheet 5 United States Patent US. Cl.112-252 1 Claim ABSTRACT OF THE DISCLOSURE An apparatus for treatingcloth-end thread in a sewing machine which is stitching cloth fed alonga linear line, by feeding cloth with air flow so that the seam crossesthe thread cutting position rearward of the stitching position, andguiding it out of the machine. The apparatus has a feeding mechanismfeeding cloth intermittently, a thread cutting mechanism and a guidetube open at one end toward the thread cutting mechanism and at theother end opening out of the machine so that the seam thread iscontinuously projecting at the fore and aft ends in the cloth feedingdirection and crossing the thread cutting mechanism.

Background of the invention This invention relates to an apparatus fortreating cloth-end threads in a sewing machine and more particularly isdirected to an apparatus for thread cutting in a sewing machine such as,for example, forming an overedge stitching seam of sewing threads evenwhen the machine is unloaded or dead sewing.

Heretofore, there has been proposed an apparatus for cutting sewingthreads cutting mechanisms which are provided in which the additionalsewing threads are caused to flow by means of air in the feedingdirection of the cloth which threads are continuously formed as theunloaded threads of seams by the operation of the sewing machine whendead sewing, i.e. sewing without cloth, or are formed at the forward andrearward ends of a cloth at the inlet of a tube the apparatus can cutthe threads by means of a shearing blade or edge in cooperation with theoperation of the machine. However, there are disadvantages such as thenecessity of considerable spac in addition to that for the sewingmachine itself so as to make possible suflicient air flow to suck thethreads into the tube until the threads are cut by means of the blade byflowing it across the blade resulting a complicated mechanism and highcost. It also shortens the life of the blade for cutting the threadssince the blade cuts finely all the unloaded sewing threads and those atboth ends of cloth together with th fine scraps of the threads produced,and when the sewing threads which are cut scatter from adjacent thecutting position for the threads or exhaust outlet of the tube thosescraps adhere at the drive portion of the sewing machine to preventdriving the machine, or they contaminate the air at the work station andso on.

Summary of the invention This invention eliminates the aforementioneddisadvantages of the conventional apparatus for cutting finely all thesewing threads of a sewing machine, and provides a novel and improvedapparatus for treating cloth-end threads in a sewing machine.

According to the present invention, there is provided an apparatus fortreating cloth-end threads in a sewing machine having a feed mechanismfor feeding cloth intermittently along a linear line, a seam formingmecha- "ice nism including a needle with a thread and looper cooperatingtherewith, a thread cutting mechanism approaching parallel with thecloth end and across the cloth feeding direction to the rear in thecloth feeding direction of the seam forming mechanism, a guide tube openat one end toward an air flow and thread cutting mechanism and at theother end open toward the outside of the machine body, a compressoradapted to be driven in response to the up and down movement of aneedle-bar, and an inverted U-shape member at the end of the guide tubewhich member has holes for ejecting the compressed air, whereby air flowcooperates with the cloth feeding between the thread cutting mechanismand the seam forming mechanism, the seam thread continuously coming inthe cloth feeding direction crosses the thread cutting mechanism.

Preferably in the apparatus in accordance with the present invention,the overedge stitching seam is continuously formed from the seam formingposition even when the rear end of the cloth fed by the cloth feedingmechanism between the upper surface of the needle-plate and the lowersurface of the cloth-presser does not reach the seam forming position,the stitching edge of the cloth is cut by the cloth cutting mechanism so.as to align the edges. The overedge stitching seam formed continuouslyeven when no cloth is present is in turn fed out in the cloth feedingdirection, but is blown into the guide tube before it arrives at thethread cutting mechanism by pressure of the air flow from the small holeprovided so as to blow the compressed air through the guide tube Withoutcutting and fed out continuously.

Preferably, when the cloth is fed to the seam forming position, theoveredging seam is formed in the cloth, and when the cloth is fed, theoveredge stitching seam not in the cloth at the rear end of the clothadvances in th direction perpendicular to that of the cloth feedingbeing carried by air fiow. When the overedge stitching seam not in thecloth arrives at the threaded cutting mechanism, the overedge stitchingseam following the rear end of the cloth is cut so that the continuouscut overedge stitching seam is blown out of the guide by air flow into atrash basket together with the waste cloth.

Therefore, one object of this invention is to provide an apparatus fortreating cloth-end threads in a sewing machine by which it is preventedfrom scattering waste cloth to dirty the atmosphere in the work area.

Another object of this invention is to provide an apparatus for treatingcloth-end threads in a sewing machine which is a simple mechanism andnot expensive.

A still further object of this invention is to provide an apparatus fortreating cloth-end threads in a sewing machine which apparatus has along life.

Still another object of this invention is to provide an apparatus fortreating cloth-end threads in a sewing machine which prevents fine wastecloth or threads from getting into the apparatus.

One feature of this invention resided in its means for causing theoveredge stitching seam not in the cloth to be blown into the guide tubeby air flow under pressure ejected from a point rearward of theclothresser, so that only the seam adjacent to the portion continuingfore and aft of the ends of the cloth is fed to the cloth cuttingmechanism so as to cut it together with the overedge stitching seam notin the cloth is divided into fine portions without cutting in a state inwhich it is continuous and long so that the portions are blown out ofthe guide tube. The necessary air flow for blowing away the seam portionis easily obtained by utilizing the up and down movement of theneedle-bar, so that the arrangement and mechanism are very simple andless expensive than the conventional machine which requires highpressure in order to suck up the seam.

Another feature of this invention is that only the overedge' stitchingseam beyond the forward and rearward ends of the cloth is cut at thecontinuing portion with the cloth, so that the life of the threadcutting mechanism is long compared with the conventional machine forcutting all the overedge stitching seams not in the cloth into fineportions.

A still further feature of this invention is that when overedgestitching seam threads are cut, they are all sucked into the guide tubeand into a waste basket, so that they are prevented from getting intothe wearing portion of the drive shaft to damage it and they are alsoprevented from scattering to dirty the atmosphere in the work area.

Other objects and advantages of this invention will further becomeapparent hereinafter, and from the drawings.

Brief description of the drawings FIGURE 1 is an overall perspectiveview of an overedging sewing machine;

FIGURE 2 is a side view of a cloth-presser provided with a feed tube forcompressed air from a compressor to the rearward thereof;

FIGURE 3 is a plan view of the presser of FIGURE 2;

FIGURE 4 is a perspective view of an embodiment of this inventionshowing operation of a thread cutting mechanism;

FIGURES 5, 6 and 7 are schematic plan views of the seam forming andthread cutting mechanism; FIGURE 5 shows the condition for dead orunloaded sewing, FIGURE 6 shows cutting threads disposed to the rearwardof the end of the cloth, and FIGURE 7 shows cutting threads disposedforward of the end of the cloth.

Description of the preferred embodiment Although specific forms of theinvention have been selected for illustration in the drawings, and thefollowing description is drawn in specific terms for the purpose ofdescribing those forms of the invention, this description is notintended to limit the scope of the invention, which is defined in theclaims.

Referring now to the drawings, and particularly to FIGURE 1, which showsa general overedge sewing machine as one embodiment of this invention,the sewing machine including an apparatus for treating cloth-end threadscomprises a pulley 1 driven by power from a source of power, a hollowbracket arm 2, a needle-bar 3 held by the hollow arm 2 interlockedthereto, a needle 4 attached to the lowermost end of the needle-bar 3, a

needle-plate 5, a cloth-presser 6, cloth cutting blade 7 for cutting thecloth prior to sewing it, a compressor 8 for producing compressed air inresponse to the up and down movement of the needle-bar 3, a feed tube 9through which the compressed air is fed to a position to the rear of thecloth-presser 6.

Referring now to FIGURES 2 and 3, which show the cloth-presser providedwith a feed tube for compressed air from a compressor to the rearthereof, the sewing machine comprises also an inverted U-shape member 10provided at the rear end of the cloth-presser 6, a small hole 11 beingprovided inside of the tube 9 so that the compressed air flowingtherethrough is ejected therefrom through a small hole 12 which openswithin the inverted U-shape member 10 toward the open side thereof.

Referring to FIGURE 4, which shows a thread cutting mechanism, thesewing machine also comprises a thread cutting blade 13, an edge 14provided at the end of the thread cutting blade 13, a shaft 15, an arm16 being held integrally by the shaft at one end, a flat mounting plate17 to one end of which the cutting blade 13 is pivotally connected bymeans of the screw 18 and at the other end of which the shaft 15 isconnected, a link 19 being connected at one end to the other end ofcloth cutting blade 13 by a pin 20. A sub-feed station 21 has the otherend of the link 19 pivotally connected thereto by means of a pin 22, ashaft 23 being pivotally driven by and in response to the operation ofthe sewing machine, an arm 24 being fixedly secured to the shaft 23, ashaft 25 being connected to the arm 24. A sub-feed tooth 26 is providedat the other end of the sub-feed station 21, a main-feed station 27including at one end a split-tail portion 28 being pivotally mounted ona screw 29 which screw is connected to the sub-feed station 21. At theother end are main-feed teeth 30, a link 31 having one end connected tothe rear portion of the main-feed station 27 by means of screw 32 andthe other end engaged with an arcuate slot 33 by means of a screw 34.The slot 33 is provided in a flat projecting portion 35 which isintegral with the arm 24. Split portions 36 and 37 are provided on theunderside of the main and subfeed stations 27 and 20, respectively. Ashaft 38 has eccentric cam 39 provided thereon and engaged between thesplit portions 36 and 37 so as to move them up and down. A fixed loweredge 40 for cutting the threads is opposed to the upper edge 13 whichmoves up and down, and a rectangular cross section guide tube 41 has anopen end parallel with the cloth feeding direction adjacent to the seamforming position, which will be hereinafter described.

In operation, when the pulley 1 rotates the needle-bar held by thehollow arm 2 interlocked therewith moves up and down reciprocally and atthe lower end of the needlebar the needle 4 and a looper (not shown)provided inside of the arm 2 form overedge seams in the cloth insertedbetween the upper surface of the needle-plate 5 and the lower surface ofcloth-presser 6. The cloth is fed by the cloth feeding mechanism, whichmoves the cloth along the upper surface of the needle-plate 5, and theend of the cloth which is aligned by cutting between needle-plate 5 andcloth feed cutting blade 7, is sewed. Although the mechanism is notshown at the top end of the needle-bar 3, the compressor 8 for producingcompressed air in response to the up and down motion of the needle-bar 3is provided, from which compressor the compressed air is caused to flowthrough the feed tube 9 to the rearward of the cloth-presser 6, wherethe inverted U-shape member 10 is provided. The feed tube 9 is formed sothat the compressed air flowing therethrough is ejected from the smallhole 11 provided inside the tube 9 and the small hole 12 open throughthe member 10 which is connected to the hole 11 through the invertedU-shaped member 10 and which opens toward the outside thereof.

The thread cutting blade 13 provided with the edge 14 at lower endthereof, as shown in FIGURE 4, is pivotally connected to one end of theflat mounting plate 17 by means of the screw 18, which plate projectsfrom the shaft 15 which holds one end of the arm 16, to the other end ofwhich cloth cutting blade is connected. The shaft 15 pivots back andforth constantly in response to the operation of the sewing machine. Oneend of the sub-feed station 21 is held inside the arm 2. The lower edge40 operates to shear the thread cooperating with the upper edge 14 whichis reciprocally rocked by movement of the thread cutting blade 13. Tothe arm 2 is secured the rectangular guide tube 41 which has one endopening parallel with the cloth feeding direction adjacent to the seamforming position, which will hereinafter be described.

Referring now to FIGURES 5, 6 and 7, which show the seam forming andthread cutting mechanism, the guide tube 41 is secured to the hollow arm2 which tube opens at one end parallel with the cloth feeding directionadjacent to the seam at which is formed position B forming overedgingseam A by the cooperation of the needle 4, looper (not shown) and thetongue 43 of the needle-plate 5, etc. as well as to the shearing portionof the upper edge 14 of the thread cutting blade 13 and lower edge 40.At the other end the tube 41 opens at the front outside of the arm 2. Asshown in FIGURE 6, to the needle-plate 5 is fixed the lower edge 42 forcutting cloth which operates to shear in cooperation with the clothcutting blade 7.

The position and direction for ejecting compressed air from the smallhole 12 of the clothresser 6 is horizontally intermediate the seamforming position B and the shearing position between the upper edge 13of the thread cutting blade 14 and lower edge 40' (as shown in FIGURE 5)so that it is disposed to eject into the guide tube 41.

The constitution of the present invention is as aforementioned. When thepulley 1 rotates, the needle-bar 3 moves up and down so that theoveredge stitching seam A is formed by the needle 4, looper and tongue43. The compressed air produced by the pump 8 by means of the up anddown movement of the needle-bar 3 is horizontally ejected toward theopening of the guide tube 41 through the tube 9 and small hole 11 of thecloth presser 6 from the small hole 12 between the upper edge 13 of thethread cutting blade 14 and lower edge 40. The arm 24 rocked by therocking operation of the horizontal shaft 23, horizontally reciprocatesthe sub-feed station 21 and its sub-feed teeth 26, and through the link35 reciprocates main-feed station 27 and its main-feed teeth 30. Themain and sub-feed stations 21 and 27 together move up and down by therotation of the eccentric cam 39 inserted between the split portions 36and 37 thereof, and by their horizontal reciprocating motion, and up anddown movement the main and sub-feed teeth 30 and 26 move generallyelliptically so that by the horizontal motion during the time theyproject above the upper surface of the needle-plate 5 cloth 44 insertedbetween the upper surface of the needle-plate 5 and lower surface of theclothresser 6 is fed toward the upper and lower edges 14 and 40. Bymeans of the reciprocally rocking blade shaft 14 the arm 16 isconstantly rocking so that by the shearing operation of the clothcutting blade 7 at its end and lower edge 43 on the needle-plate 5 forcutting cloth the stitching edge of the cloth 44 is cut to align itsedges. Further, the thread cutting blade 14 is so disposed that duringup and down motion by the eccentric cam 39 when the blade shaft 15 rockscounterclockwise the main and sub-feed stations 27 and 21 raise, and onthe contrary, when the blade shaft 15 rocks clockwise they lower. Whenthe blade shaft 15 rocks counterclockwise together with mounting portion17 so that the sub-feed station 21 raises, the thread cutting blade 14rocks clockwise around the stepped screw 18 as a center so that theupper edge 13 and lower edge 40 operate to shear. On the contrary, whenthe blade shaft 15 rocks clockwise together with the mounting portion 17so that the sub-feed station 21 is lowered, the thread cutting blade 14rocks counterclockwise around the stepped screw 18 as a center so thatits upper edge 13 raises upwards from the lower edge 40. These motionswill be repeated continuously.

As aforementioned the sewing machine operates, and the overedgestitching seam A is continuously formed at the seam forming position Beven when there is no cloth present. As the rear end of the cloth 44 isfed by the main and sub-feed teeth 30 and 26 between the upper surfaceof the needle-plate 5 and the lower surface of the cloth-presser 6,although it at first does not reach the seam forming position B, thestitching edge of the cloth 44- is cut by the cloth cutting blade 7moving up and down and lower edge 42 so as to align the edges. Theoveredge stitching seam A formed continuously is in turn fed out in thecloth feeding direction, but is blown into the guide tube 42 before itarrives at the shearing portion between the upper edge 13 of the threadcutting blade 12 and lower edge 40 by pressure of the air flow ejectingfrom the small hole 12 of the cloth-presser 6, passing through the guidetube 41 without being cut and being fed out continuously forward of thearm 2.

Next, when the cloth 44 reaches the seam forming position, the overedgeseam A is formed in the cloth 44 the edges of which are aligned, andwhen the cloth 44 is fed, the overedge stitching seam A previouslyformed outside the cloth at the rear end of the cloth 44 advances in thedirection perpendicular to that of the cloth feeding due to the airflow. When the overedge stitching seam A not in the cloth arrives at theshearing portion of the upper edge 13 of the thread cutting blade 14 andlower edge 40 performing the shearing action continuously as shown inFIGURE 6, the overedge stitching seam A not in the cloth at the rear endof the cloth 44 is cut so that the cut off overedge stitching seam A isblown out of the inside of the guide 42 by air flow forward of thesewing machine and into a trash basket together with the waste cloth,etc.

Furthermore, when the over stitching of the right end of the cloth 44 iscompleted so that the cloth 44 reaches the position where it is notsubject to the cloth feeding action by means of the main and sub-feedteeth 39 and 26 as shown in FIGURE 7, since the overedge stitching seamA continues to be formed as a continuation of the overedge stitchingseam at the forward end of the cloth 44 even if the cloth 44 is nolonger present, the overedge stitching seam A not in the cloth disposedbetween the forward end of the cloth 44 and seam forming position Bgradually increases its length and forms slack, the slack being blowninto the guide tube 42 by the air flow. When the overedge stitching seamA not in the cloth extending from the forward end of the cloth 44crosses the shearing portion of the upper edge 13 of the thread cuttingblade 14 and lower edge 40 which are continuously shearing, the overedgestitching seam A not in the cloth and extending from the forward end ofthe cloth 44 is cut so that the cut overedge stitching seam is blowninto the guide tube 42 by the air flow as shown in FIGURE 5 so as to befed out continuously at the forward end of the arm 2.

As aforesaid, since the present invention provides the means for blowingthe cut off overedge stitching seam into the guide tube by the air flowunder pressure ejected at a position rearward of the cloth-presser, onlythe seam adjacent to the portion extending from the fore and aft ends ofthe cloth is fed to the shearing portion of the thread cutting blade soas to be cut. The overedge stitching seam not in the cloth is dividedinto fine portions so that they are blown out from inside the guidetube. Due to the easy obtainability of the air flow for blowing away theseam by utilizing the up and down movement of the needle-bar, thearrangement and mechanism are very simple and less expensive than theconventional system for requiring high pressure in order to suck theseam up. Also, inasmuch as only the overedge stitching seam extendingfrom the forward and rearward ends of the cloth is cut, the life of thethread cutting blade becomes long compared with the conventional systemfor cutting all the overedge stitching seam not in the cloth into fineportions. In addition since the cutting fine waste threads of thestitching thread not in the cloth are not produced, the sewing machineis protected from them getting into the drive shaft bearings, etc., andthe waste threads are not scattered to dirty the atmosphere in the workarea.

Although in the aforementioned embodiment the ejecting opening of thecompressed air is provided at the clothpresser, it will be easilyunderstood that a nozzle, etc., separate from the cloth-presser can beprovided to obtain the same effect. Though in the aforesaid embodimentthe compressed air is produced by utilizing the up and down movement ofthe needle-bar, it will be easily understood that compressed air can beobtained by utilizing any other drive portion of the sewing machine or aseparate compressor from the sewing machine.

What is claimed is:

1. In a sewing machine for continuously forming an overedge stitchingseam line at the edge of a cloth, said machine having a needle mechanismmovable vertically with a thread therein, means for compressing aircoupled to said needle bar and actuated by the vertical movement of theneedle bar, means for feeding a cloth intermittently in synchronizationwith the movement of the needle mechanism, and a rockable loopermechanism along a straight line therebetween; an apparatus for treatingthe seam end threads comprising:

a cloth cutting mechanism having a cutter movable vertically andreciprocally across the plane of the cloth for cutting the end of thecloth along a line on which the seam line is to be formed, said clothcutting mechanism being upstream, in the cloth feeding direction, fromthe needle and rockable looper mechanism, and a reciprocating rotatingshaft coupled to said cutter for moving it;

a thread cutting mechanism having a fixed cutter and a movable cuttermovable vertically and reciprocally and cooperating with said fixedcutter, said movable cutter being coupled to said shaft for operatingsaid cloth cutting mechanism, said cutters being positioned parallelwith the cloth end at the downstream, in the cloth feeding direction,from the needle and rockable looper mechanism;

a cloth presser having a port therein directed horizontally and coupledto said means for compressing air for ejecting a stream of compressedgas produced by the elevational movement of a needle bar, the stream ofgas being directed across the cloth feeding direction intermediate theneedle mechanism and rockable looper mechanism and the thread cuttingmechanism; and

a guide tube opening at one end opposite said port in out of the sewingmachine.

References Cited UNITED STATES PATENTS 1,214,170 1/1917 Kiewicz 112-2523,058,438 10/1962 Russell et al. 112252 3,143,987 8/1964 Daniel et al.112252 3,182,620 5/1965 Hornberger 1l2252 3,217,680 11/1965 Harris eta1. 112-252 3,242,892 3/1966 Fowler 112-252 3,356,054 12/1967 Southwellet al 112252 3,379,151 4/1968 Tiemann 112-252 3,380,416 4/1968 Dubuis112252 FOREIGN PATENTS 1,424,672 12/1965 France.

HERBERT F. ROSS, Primary Examiner

